CF8 Joomla: Emails sending from Preview but not Frontend

I am using CF8 on Joomla.

The form sends and receives emails only from the preview mode, but not from the frontend.

Both the PHP mail test and the SMTP mail test within the system configuration return a positive result, and the test emails arrive regularly. The debug log does not return any errors

How can I resolve this issue?

Hi nicola

Does the form send email when you use the "Front" preview link in the forms manager ?

If not then what is the debug shown after your finish the form ? (please remove any sensitive info from the debug before posting it)

Hi Max, 

thank for your reply. The form send email only when I use the preview link in the form manager. When I test it in frontend (on line website) doesn't send any mail.